Elements from the Sea
No description yet. This curated deck is ready for daily study.
Card preview (24)
State the appearance and state of Chlorine at room temperature. Halogens
Pale yellow/ green gas.
State the appearance and state of Bromine at room temperature. Halogens
Brown/ orange/ red liquid.
State the appearance and state of Iodine at room temperature. Halogens
Dark grey solid.
What do oxidation states show? Oxidation states
An atom’s oxidation state tells us how many electrons it has donated or accepted to form an ion or a bond.
Why does an ionic substance need to be molten or in solution before you can electrolyse it? Electrolysis
An electric current can only pass through an ionic substance when its ions are free to move about.
Describe how you would set up the equipment for the electrolysis of a solution of aqueous copper sulfate. Electrolysis
• Connect each electrode to the power supply. • Place the electrodes into a beaker containing a solution of aqueous copper sulfate, making sure that the electrodes aren’t touching each other. • Turn the power supply on.
What is formed at the anode when a concentrated halide solution is electrolysed? Electrolysis
The halogen will be formed at the anode.
Two carbon electrodes are placed into molten copper chloride and the power supply is turned on. What would you see happening at the anode? Explain your answer. [2 marks] Electrolysis
At the anode, you would see bubbles of gas appearing because chloride ions are losing electrons to form chlorine.
Two carbon electrodes are placed into molten copper chloride and the power supply is turned on. What would you see happening at the cathode? Explain your answer. [2 marks] Electrolysis
At the cathode, you would see the electrode being plated because copper ions are gaining electrons to form copper metal.
What is brine? Electrolysis
• a solution of water with high concentrations of salts - mainly sodium chloride, but also some bromine and iodine salts • occurs naturally in salt lakes and seawater, and can be made by dissolving rock salt in water
Describe what occurs at the cathode. Electrolysis
positive cations move to the negative electrode, the cathode, and gain electrons. REDUCTION
Describe what occurs at the anode. Electrolysis
negative anions move to the positive electrode, the anode, and lose electrons. OXIDATION
How do you calculate percentage atom economy?
molecular mass of desired product / sum of molecular mass of all reactants x100
What does REDOX stand for? Redox reactions
Reduction is Gain of electrons. Oxidation is Loss of electrons.
What happens to the oxidation state of a substance when it’s reduced? Redox reactions
The oxidation state will decrease.
During a redox reaction, an oxidising agent _____ electrons and is _____. Redox reactions
During a redox reaction, an oxidising agent gains electrons and is reduced.
What is a reducing agent? Redox reactions
A substance that is oxidised. It donates electrons.
What happens to the oxidation state of a substance when it’s oxidised? Redox reactions
The oxidation state will increase.
During a redox reaction, a reducing agent ____ electrons and is ______. Redox reactions
During a redox reaction, an oxidising agent loses electrons and is oxidised.
What is an oxidising agent? Redox reactions
A substance that is reduced. It accepts electrons.
Use oxidation states to balance this redox reaction: Ca(s) + Al³⁺(aq) → Ca²⁺(aq) + Al(s) [1 mark] Redox reactions
3Ca(s) + 2Al³⁺(aq) → 3Ca²⁺(aq) + 2Al(s)
What colour solution is formed when iodine dissolves in cyclohexane? Halogens
purple
What colour solution is formed when bromine dissolves in cyclohexane? Halogens
Red/ brown
What colour solution is formed when chlorine dissolves in cyclohexane? Halogens
Pale green